CABI study unearths important lessons for the fight against fall armyworm

A study by CABI contributes important knowledge on fall armyworm (Spodoptera frugiperda). CABI’s research findings suggests that employing more sustainable and environmentally friendly solutions could help mitigate the damaging impacts of the species.

Published in CABI Agriculture and Bioscience, the article explores the economic impacts and management of fall armyworm in smallholder agriculture in Ghana, one of the many countries to have recently fallen victim to infestations of the pest. CABI’s teams collected survey data in two rounds (2018 and 2020) from 370 smallholder households in the major maize-growing areas of the country.

The study found that following the increased adoption of biopesticides and cultural practices for fall armyworm management, the maize yield losses in Ghana were not as severe as initially predicted.

Dr. Justice Tambo, lead author of the study and Senior Socio-Economist at CABI said:

″Unlike in the early years of the fall armyworm invasion, there has been reduced intensity of pesticide use and increased use of protective equipment (PPE) when spraying pesticides, and consequently less incidence of acute pesticide poisoning among maize farmers.″

These findings could have important implications for efforts to control the pest not only in Ghana, but also elsewhere.

The march of the fall armyworm

Native to the Americas, fall armyworm has spread like wildfire across parts of the globe. In 2016, there were only six countries in Africa with documented sightings of the pest. According to the FAO there are now around 80 countries in Africa, the Near East, Asia and the Pacific with cases of the species.

The voracious pest has an appetite for over 80 varieties of crops, but it prefers to feed mostly on maize. The larvae burrow into the crop’s stem and cob at various stages of its lifecycle, which renders the maize useless.

Maize is the world’s second most produced crop, after sugar cane, and the most farmed cereal grain by some margin. The crop is crucial to the economies of many African states. It is a staple food for an estimated 300 million Africans. Estimates suggest that, without remedial action, fall armyworm could reduce Africa’s maize supply by between 8.3 and 20.6 million tonnes per year.

Although fall armyworm is impossible to eradicate, it can be controlled. The most popular method for this is through the application of pesticides. But this approach has harmful effects on human and animal health. Using chemical pesticides also damages the environment and can deter natural enemies of fall armyworm .  

Ghana’s maize economy and fall armyworm

First detected in Ghana in late 2016, fall armyworm quickly established itself as the dominant pest for the country’s maize. The crop accounts for over 50% of the nation’s total cereal production. A 2018 evidence note by CABI revealed that maize farmers had average losses of 26.6% in Ghana due to infestations.

When fall armyworm invasions first started, farmers opted to use pesticides as the most popular counter method. In 2017, Ghana allocated USD 4 million to procure and distribute pesticides as an emergency response to the invasive pest. Research from 2018 has documented how Ghanaian farmers’ failure to take preventive measures, such as using PPE, has had harmful impacts on their health.

A national multi-stakeholder task force was created and charged with advising Ghana’s Minister of Food and Agriculture and coordinating the response to fall armyworm.  Authorities also launched public information campaigns to increase awareness of fall armyworm and promote sustainable management practices.   

CABI’s researchers wanted to better understand if and how these measures had affected farmers’ behaviour. And gauge the economic impacts. The team collected survey data from farmers in 2018 and the same households were revisited in 2020.

Breakthrough findings

CABI’s scientists found that the rates of fall armyworm infestation in smallholder farmers’ fields were lower in 2020 than 2018. What’s more, smallholder farmers were resorting to IPM and agroecological approaches for combating fall armyworm, in line with recommended practices. There was greater adoption of preventive cultural measures, such as timely planting, regular weeding and fertilizer application. Plus, intercropping and rotation with non-host plants.

While farmers continued to use chemical pesticide, they applied it more sparingly. There was also an increase in the use of biopesticides. PPE items were also being used more frequently when spraying pesticides.  

Worst-case scenario estimates made in 2017 suggested Ghana’s maize production could be reduced by 45%, equivalent to US$ 284.4 million in lost revenue, due to fall armyworm invasions. But findings from the survey data from 2017 and 2020 indicate that there was up to a 14% (statistically insignificant) reduction in maize yields for household experiencing fall armyworm infestations compared to those without. This suggests that initial forecasts may have been overestimated. The various actions taken to tackle fall armyworm in Ghana, and a build-up of natural enemies, may have led to this marked reduction in the economic losses incurred.

Towards more effective and sustainable approaches

As the problem of fall armyworm persists and cannot be eradicated, there is an urgent need to increase the promotion of sustainable and environmentally friendly solutions to mitigate its impacts. While using pesticides is still a popular approach among smallholder farmers across many parts of the world, it carries risks to human health and the natural enemies of the species. This means improving farmers’ knowledge of safe pesticide use practices will be crucial.

Incentivising the adoption of safer alternatives to synthetic pesticides, such as biopesticides and IPM could be an effective pathway for policymakers. Looking to the future, governments could invest in the development and promotion of resistant varieties of maize. Plus, biological control agents, which could help reduce the reliance on pesticides.

Read the study in full:

Tambo, J.A., Kansiime, M.K., Mugambi, I. et al. Economic impacts and management of fall armyworm (Spodoptera frugiperda) in smallholder agriculture: a panel data analysis for Ghana. CABI Agric Biosci 4, 38 (2023). https://doi.org/10.1186/s43170-023-00181-3

This research was financially supported by the United Kingdom (Foreign, Commonwealth & Development Office) and the Netherlands (Directorate-General for International Cooperation) through CABI’s Action on Invasives programme.